Why is my 2012 Mac Pro DisplayPort not working?

Question

Why is my 2012 Mac Pro DisplayPort not working?

I have a mid 2012 Mac Pro running Catalina that is working fine when connected using HDMI.

I want to use the DisplayPort on the GTX 680 video card instead of the HDMI connection. When using the DisplayPort connection, I get no display at all on my monitor, but the Mac still boots up fine. I just can't see the display.

How can I get this DisplayPort connection working?

Mac Pro is connected from the DisplayPort on the Mac to a DisplayPort KVM. The KVM is then connected to my 40" Samsung 4K display using HDMI. The KVM does not have any HDMI inputs. The Samsung display does not have any DisplayPort inputs.

This setup has been working for years on my Windows based machines and I want my Mac Pro going through the KVM.

Mac Pro, macOS 10.15

Posted on Nov 13, 2022 1:09 PM

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Answer 1

Nov 15, 2022 4:35 PM in response to Community User

connected through many a switch, you still need the EDID secondary channel connection all the way through to the display at those certain times I mentioned.

Set aside the KVM switch and connect directly.

Once you know that works, then try using the Switch, keeping in mind that the Mac must "see" the display (each and every time) to be able to light it up.

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Answer 2

Nov 13, 2022 2:39 PM in response to Community User

The Mac uses a system that reminds me of “Plug and play” to determine what display is connected, and what its capabilities are.

To get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• hold the Option key while you click on the (Detect Display) button that will appear in Displays preferences (from another display)

so try doing some of those things and see if the display comes alive.

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Answer 3

Nov 15, 2022 7:39 AM in response to Grant Bennet-Alder

Tried these things and still no joy.

I can't use the Detect Display button because I can't see the screen to get to it. If I get to my desktop, is there a set of keystrokes I can use to get there blindly?

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Why is my 2012 Mac Pro DisplayPort not working?

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